From: Paul Khuong <pvk@pvk.ca>
Date: Sat, 8 Jun 2013 01:43:16 +0000 (-0400)
Subject: New VOP for LOGAND of bignum and word-sized constant on x86-64
X-Git-Url: http://repo.macrolet.net/gitweb/?a=commitdiff_plain;h=91a5cbf7375439309fede4776d8debc7a132dc20;p=sbcl.git

New VOP for LOGAND of bignum and word-sized constant on x86-64

 We can directly read the first bignum digit and AND it.
---

diff --git a/src/compiler/x86-64/arith.lisp b/src/compiler/x86-64/arith.lisp
index 76f3b00..9229626 100644
--- a/src/compiler/x86-64/arith.lisp
+++ b/src/compiler/x86-64/arith.lisp
@@ -1891,6 +1891,27 @@ constant shift greater than word length")))
     (move ecx count)
     (inst shl result :cl)))
 
+(define-vop (logand-bignum/c)
+  (:translate logand)
+  (:policy :fast-safe)
+  (:args (x :scs (descriptor-reg)))
+  (:arg-types bignum (:constant word))
+  (:results (r :scs (unsigned-reg)))
+  (:info mask)
+  (:result-types unsigned-num)
+  (:generator 4
+    (let ((mask (constantize mask)))
+      (cond ((or (integerp mask)
+                 (location= x r))
+             (loadw r x bignum-digits-offset other-pointer-lowtag)
+             (unless (eql mask -1)
+               (inst and r mask)))
+            (t
+             (inst mov r mask)
+             (inst and r (make-ea-for-object-slot x
+                                                  bignum-digits-offset
+                                                  other-pointer-lowtag)))))))
+
 ;; Specialised mask-signed-field VOPs.
 (define-vop (mask-signed-field-word/c)
   (:translate sb!c::mask-signed-field)